Drafting instrument.



N0. 893,085. PATEN'I'ED JULY 14, 1908. L. R. LOUGHBOROUGH. DRAFTING INSTRUMENT. APPLICATION FILED Nov. 1,1, 1907.

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UNITED sTATEs PATENT oEErcE.

A LEROY-R.l LoUcHBoRoU'cH, or ROCHESTER, NEw YORK.

DRVAFTING- INSTRUMENT.

Specification of Letters Patent.

Patented Jury 14,A 190s.

Application led November V11, 1907. Serial No. 401,646. I

To all whom it may concern:

Be it known that I, LEROY R. LoUGHBoR- OUGH,A a citizen ofthe United States, residing at Rochester, in the county lof Monroe and State of New York, have invented a new and useful- Improvement in Drafting Instru-A `its graduations with openings which are adapted to receive a pencil point, so that arcs or circles o i' different diameters may be inscribed by inserting the pencil point in one or another cf said openings. An instrument of this kind is shown and described in Letters Patent ofthe United States No. 844,157, granted to me February 12,' 1907.

The object of my present invention is to simplify the construction of lthe means whereby the centerfpinmay be adjusted, as

required.

In the accompanying drawings: Figure 1 is a side elevation of `a triangle embodyingv the invention.` Fig. 2 isa fragmentary side elevation of the same, on an enlarged scale, omitting the'pin-retaining spring. Fig.y 3 is a similar view, partly in section, showing the spring in place.

Similar letters of reference indicate corresponding parts throughout the several views. One of the bars ofthe instrument, preferably the base bar A, is in the form of a scale oc-ruler havingfthe customary graduationmarks along its outer edge.

- -When the instrument is in the form of a triangle, it may be vcombined with a protractor B and an angle bar' Cof forty-live de grees, as shown; but these additional features are-optional.

d indicates the openings in the4 bar A which are adapted to receive a marking or pencil point and which `are preferably spaced 'uniformly and arranged to coincide with nu- .mcrous graduations of said bar, such as thev inch, half-inch, quarter-inch and eighth-inch marks, as shown lin the drawings.` -These openings I nay be of any suitable shape,but are preferably circular and provided above or below the same with a clrcular enlarge-- ment d1, as shown. These enlargements permit the underlying-paper or object to be seen a short distance in advance ol?l the. pencil point.

v ,M At the initial or left hand end of the series of pencilopenings d is arranged an aperture E, the upper edge of which is in line with said row of openings 'and provided with a longitudinal series of notches or seats f adapted to receive an ordinary pin or center-g about which the instrument is turned in using it as a compass, as above described. These notches which constitute an auxiliary scale are spaced to form equal divisions or frac. tions of the spaces betwern adjacent openings d, so that, if for example, it should be desired to inscribe a circle having a radius equal to an inch and a fraction of an inch less than the smallest graduation represented by 'adjacent openings d, this can be done by placing the pin gin the corresponding seat f. In the construction shown, the pencil-openings d correspond tov graduations represent ing-aneighth of an inch, while the pin-seatsf are spaced to represent'thirty-seconds of an inch. s

'H indlcates a spring or elastlc tongue exi tending across the Jfront sides of the pin-seatsf l and serving to retain the center-pin in any seat in which it may be placed. The'seats are preferably somewhat shallower than the thickness or diameter of the pinso that the s ring is delected by the pin u on inserting t e latter in a seat, as shown in Fig. 3, thus reliably holding the pin therein. The spring is secured in place by any suitable means. In the preferred construction shown, its left hand end is secured in a slot i extending downwardly from -the contracted end of the aperture E and having lateral enlargements or holes 'i which communicate with the slot. After inserting the lower end ofthe spring in this slot, itis reliably conined therein by plugs or rivets j driven into said holes, the. rlvets expanding and clamping or inchlng the spring against the walls of the s ot. bThe en largements 'il are preferably arranged on o pil posite sides of the slot and out of line with each other, as shown, so that .the .rivets clamp the spring at different points.

This

spring forms a simple, neat and inexpensive .inch and half-mch graduations of the main scale'are numbered 1,2, 3 etc. Bythis arrangement, upon inserting a p ln 1n the zero seat fand placlng a penc1l-po1nt say 1n the i substantially as set forth.

opening marked 1, the diameter of the inscribed circle Will be one inch. If, for example, it is desiredto inscribe a circle having a diameter of`one inch and a sixteenth, the pencil point-isplaced in the same o ening, but the pin is shifted one notch to t e left; While if thel circle is to have a diameter of one yinch and an eighth, the pin is shifted two notches to the left, and for a circle of an inch and three sixteenths, the pin is placed in the extreme left hand notch.

I claim as my invention l1. An instrument of the character deL scribed, comprising a bar having a roW of openings adapted to receive a marking point and a series of seats for a center pin spaced relatively to said openings, and means for retaining a center-pin in one of said seats,

l said row of openings, one edge of said aperture being in linewith said row of openings and 'having' a series of pin-notches, and an ses/,085'

elastic member extending across the front side'of said notches, substantially as set forth.

4. An instrument of the character described, comprising a bar having a row of openings adapted to receive a marking point and an aperture arranged near one end of said roW of openings, and provided in its edge with a series of pin-notches, said aperture-having a slot provided with an enlargement, a spring seated with one end in said slot and extending with its free portion across said notches, and a plug arranged in said enlargement and bearing against said spring, substantially as set forth.

5. An instrument of the character dclscribed, comprising a bar having a row of openings adapted to receive a marking point and an aperture arranged near one end of said roW of openings and provided in its edge With a series of pin-notches, said aperture having a slot provided at opposite sides with enlargements arranged out of line with each other, a spring seated with one end in said slot and extending with its free portion across said notches, and plugs driven into said enlargements and bearing against said spring, substantially as set forth.

Witness my hand this 29th day of October, 1907.

LEROY R. LOUGHBOROUGH. Witnesses:

C. F. GEYER, E. M. GRAHAL 

